Idling Your Car In The Winter Isn't Necessary

If you've ever borrowed your brother's car on a cold winter day, he might've sternly requested for you to let the car engine idle for at least five minutes before driving to school. (Not that we have any experience with that...) But is this advice valid? Nope—not anymore.

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But Wait, Why?

In a 2009 study of costly myths, researchers found that Americans thought they should idle their cars (that's running the engine without actually going anywhere) for at least five minutes before driving when temperatures were below freezing. False! While it's true that cars are at least 12 percent less fuel efficient in the winter, and it does take longer for the engine to heat up, that doesn't mean you need to idle your car. The last time it was necessary was during the 1980s and early 1990s, when older cars relied on carburetors. A carburetor's job was to mix the right amount of gasoline with air for the engine to run properly.

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Why Things Changed

Carburetors became obsolete once electronic fuel injections were introduced to the car industry. According to The Washington Post, these use "sensors to supply fuel to the engine and get the right air and fuel mix. ... The sensors monitor and adjust to temperature conditions." So, basically, idling a car today offers zero benefits to modern cars. The Environmental Protection Agency and Energy Department elaborate that "the engine will warm up faster being driven." So every minute you idle your car, you're just wasting fuel and contributing to greenhouse gas emissions. In an experiment performed by Natural Resources Canada, researchers found that total fuel consumption increased by 7 to 14 percent with a 5-minute warm-up, and consumption increased by 12 to 19 percent with a 10-minute warm-up.

Not only is idling an environmental no-no, turns out that, depending on where you live, it might also be illegal. In Ohio, for example, idling your car at any time is strictly forbidden. The engine anti-idling law in Washington, D.C. states that: "Motor vehicles powered by gasoline or diesel are not allowed to idle for more than three minutes while the vehicle is parked, stopped or standing. Any person or organization owning or operating a vehicle seen violating this regulation will be issued a civil infraction ticket for $1000 for a first-time violation." (When temps drop below freezing, the grace period extends to five minutes.) Wondering if you can legally idle? Look up your home state on the EPA's anti-idling regulations.

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